finish off, deliver the final blow (so to ensure (something) is dead) / (idiomatic) deliver the final blow (so to ensure (someone or something) to have no hope for recovery)

pierce; stab; stick / (of an insect) sting; bite / cause a sharp or stabbing sensation in (such as pain or smell) / (baseball) tag out

stopping

once

last, end, conclusion / last, final

a single punch, a hit, a blow

to punch, to strike, to hit once

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

(video games) OHKO, a one-hit knockout; defeating an opponent with a single attack

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend